PTR can refer to:
- PTR Record or pointer record, a type of DNS record in computer network configuration
- Product and Technical Review, a technical design review presentation and documentation package
- PetroChina (NYSE: PTR), a Chinese oil company
- Physikalisch-Technische Reichsanstalt, historical name of a German research institute, now called Physikalisch-Technische Bundesanstalt
- Pool Test Reactor, a Canadian nuclear reactor
- Professional Technical Reference, a category of books published by Prentice Hall
- Planar ternary ring, an algebra used to coordinatize projective planes.
- Plastic tank radiator, a type of automotive radiator with a plastic tank and metal core
- Public Test Realm, a World of Warcraft server for previewing new content
- Popstars: The Rivals, a British talent show
- Paid to read, a type of online incentive-based advertising where members receive payment for reading emails with ads and for clicking on advertisers' links
- Parappa the Rapper, a video game for the Sony PlayStation
- Paper Tape Reader, legacy name for a general-purpose RS-232 input device under CP/M
- Particle Transfer Roller, a device for cleaning motion picture film
- Proton-transfer-reaction mass spectrometry, a chemical analysis technique.
- Pitrilysin, an enzyme